Vulcanizing-mold.



P. W^..LITCHFIELD. VULGANIZING' MOLD. APPLICATION FILED MAY 22, 1909.

Patented Dec. 28, 1909.

' eis-resse.

PAUL 'W'. LITCHEELD, OF AKRON, OEIO, RUBBER CIVIPANY, OF AKRON,

Assisnon vrro 'ri-1E eoonYnnn TIRE AND omo, n .conronnrron or omo.

vULonmzme-Motn.

Application filed May 22,

Akron inthe countyvof Summit yand State of Ohio, .have invented new and useful` Imy provements in Vulcanizing-llolds, of which Vnary results frointhe same.

the following is a specification.

This invention relates to molds for vulcanizing elastic articles such as vehicle tires. :H eretoi'ore in the manufacture of vehicle tires, either of the solider pnemuaticv type, when i'twas sought to provide the tread of the tire with a peculiar design, the result was accomplished by cutting or forming the design in the metal of the wall of the mold. This was usually easily accomplished by theV use of a suitable machine where the design .to be produced upon thetire was formedupon curvilinear lines, but if on the contrary, tlie'design was angular Ain conformation, tlie'lorming of. the designv in the metal `of the moldwas exceedingly diliicult and very expensive, Experience has also shown that where protuberances are to be formed on the t surface of the tire the corresponding recA ses in. the mold 4must each be provided with a suitable vent to permit the escape of air to allow .the recesses to properly fill with the tire material, thns necessitating a separate vent for .each ofthe recesses in order to obtain satisfacln view of the objections existing to the toregoinglmethod or" manufacturing molds, the object of this invention, broadly speaking, isto provide a mold for the vulcanization of velast-ic vehicle tires 'having a re-l movable portion, upon the `inner surface of which any selected design may be' easily formed when the portion is detached from the 'mold and when inserted therein and` constituting a portion thereof produces in the finished tire the desired design.

The invention also contemplates making theV removable section of the mold of a plurality of separate rings, vthe inner faces of each of which arearranged te constitute a portion of the inner mold surface and-each el? which may be separately subjected-to a tool for producing the desired design therein. By forming this detachable portion of a plurality of rings, the inner surface of each ot the ring'swill constitute a yportion et the complete design to beimparted to the snrace of the' tire .and whenassembled ,and

' Specification of Letters Patent.

Iatented Dec'. 28, 1909. 190e serian No. 497,683.

lmounted in thel mold the complete design will be formed von the tire.

Vith the foregoing-and other objects in view, the invention consists -in the novel construction, combination and arrangement- ,of partsconstituting the invention to ,be hereinafter specilically described and illustrated in the accompanying drawings which form a lparthereof wherein is shown the preferred embodiment of the invention, but it is to be understood that changes, variations and modiiications can be resorted to which come within the scope of the claims hereunto appended.

In the drawings in which similar reference numerals indicate like parts in the ldii'- i'erent ligures: Figure .l is a cross sectional view of atire mold embodying this invention. Fig@ is a view of a tire which has been formed in a mold such as shown in Fig. l and used to' illustrate the operation of the same. Fig. 3 is a view in side elevation of a ring employed vin connection with this invention. Fig. l is a view similar to Fig ot a plurality ot rings in alineinent with each other with the notches oi' vone ring Aalternating with-'respect to the notches of adjacent ring-sf Fig. 5 is an inverted plan of a plurality of rings such as shown .in Fig. 3 with the notches therein in transverse alinement; and, Fig. 6 isa view similar to Fig. 5 with the notches in each ring alternating with respect to thenotches of adjacent rings. i v

liteferring.V to. the drawings in detail, the referenceIn llerals l and 2 denote moldsections, preferably ot' the general type shown, having in their faces semi-'circular grooves, which when the molds are-united constitute -a mold cavity v3. The mold members are provided atintervals with laterally projecting registering apertured lugs ,l through which extend bolts 5 for clamping them together. The `inner faces of the mold members 1 and 2 areagls'o provided with circumferentially extending rabbets, which together form a circumferentially-eXtending` recess 6. lopen communication with the mold cavity 3 and is preferably placed on the outer portion thereof solas tobeopposite the tread 4oi' the'tire placed in the cavity 3. Mounted'in the recess 6 are ai plurality of rings, des1gnated inthev drawings byy the-reference 11umerels 7, 8,I 9,10, 11 and 12 which-are used.

inner oppositely-,disposed This recess is in llO to illustrate this invention, but it Will be understood that the number of rings may be increased or diminished as desired and still be within the scope of this invention, the number of rings employed being governed largely by the peculiar nature of the design which it is sought to produce on the tread portion of the tire.

The design Whichthe rings shown in the drawings are capable of producing lconsists in a plurality of protuberances 13 alternating in position with recesses 1li the protuberances and recesses being arranged in both longitudinal and transverse alternating series so that the protuberances of one circumferential series alternate transversely with the recesses of the adjacent longitudi. nal series and the recesses of each longitudinal series also alternate transversely with the corresponding protuberances of adjacent series.-

In constructing the mold, one half of the rings are placed in the rabbet in one mold member' and the other half of the rings inthe rabbet in the other mold cavity and are severally held in position through the medium of holdfast devices Each mold member is then placed ina suitable machine and the semi-circular grooves Which form the mold cavity 3 are accurately turned, during which operationv the inner facesof the rings are also shaped-'to conform'to the general outline of the cavity 3. The rings arel then reincved and are clamped together in transverse registering relation. in suitable machine and a plurality of transverse grooves 1G are cut therein, as shown'in Fig. 5, after which the. rings are placed in their respective rabbets in the mold members, during which operation the recesses or grooves in adjacent rings will be arranged in ystaggered relation with each other, as shown in Fig. 6. The rings are secured in place by the lioldfast'v devices' l5.` An unvulcanized tire is then placed in thecavity' 3 and the mold members clamped together by the bolts 5 and the mold With its contents subjected to a vulcanizing heat, durin Which the tire -material expands suiiiciently tov fill the recessesl 16 in. the rings, and the design. formed on the rings is imparted to the tread ofthe tire, as clearly shown in Fig. 2. -4

Experience has shown that'there is sutlicient leakage of air outwardly both between the rings land the Walls of the rabbets in which they are mounted to permit the-material 'of the tire to freely expand into the recessesy 416, thus avoiding any danger ofY trouble in the. formation of. a perfect design in the finished product corresponding to the design formed on the inner facesof the rings.

It will be obvious that otherdesig'ns may be cut on fthe interior. of the .rings .and the number of rings maybe varied accordingly vand still be within-the scope of this inven-v tion. It ivill also be apparent that when grooves in their abutting yfaces forming a mold eavity,each of said members provided with a recess communicating with said cavity and a plurality' etti-ings mounted in said recesses, the inner faces thereof being recessed, the recesses in each ring alternat' ing in position' with respectto the recesses in the adjoining' rings. the inner faces of said rings adapted to eoi'i'stitute a portion of the outer wall of said mold' cavity and receive the outer surface of au article vulcanized therein for producing on the outer surface thereof the design formed on the inner faces of said rings. A

A vulcanizing moldcomprising unan nular body formed with a mold cavity and furthermore provided with a circumferentiallysextending recess opening into said cavity, a plurality of rings mounted in said of spaced recesses, the recessesof one ring beingpalterlnately disposed with respect to the recesses of the other ring.

3. A vulcanizing mold comprising an an nular body formed with a mold cavity and furthermore*provided with a circumferenti'ally-extending recess .opening into said cavity, a. plurality of rings mounted in said recess and each provided in the edge thereof which opposes the mold cavity with a series of spaced recesses, the recesses of one ring being alternately disposed With respect to the recesses of the other ring, each of said rings havingl that edge which opposes'the mold cavity segment-shaped in cross-section and each of said rings having theinner` Wall of 'each of its recesses segment-shaped in cross-sectio1nsaid rings having the edoes which oppose the mold-cavity flush with each other.

et. A vulcanizmg mold comprising an annular body formed with a mold cavity and r furthermore provided with a circumferenfurthermore provided With a circumferen- 'tially-,extending recessopening into s aid cavity, aserles of rlngs mounted 1n sald recess and each provided in the edge thereof which opposes. the mold cavity with a series of spaced recesses,'the recesses of one ring be ing alternately disposed with respect tothe recessesof the, other ring, the .outer rings of the series being thicker than the. intermediate rings. i Y' 6. A- collapsible mold comprising an annular bodyprovided With a series of annu lar members arranged within said body and each having aworking edge provided with a circumferentially-extendlng seriesv of recesses, therecesses of one member alternatelydisposed With respect to the recesses of the other member.l y

7 A collapsible mold comprising an annular body provided with a series of annular` members arranged Within said body and each 8. A vulcamzmg apparatus comprising a body port-ion provided vwith a plurality of annular members each having a Working face provided with recesses, the recesses of one member alternately-,disposed with respect to the recesses of the other member whereby the uli-recessedportions of adjacent members will constitute side walls of the recesses of the other members.l

9. A vulcanzing mold comprising co erating' separable sections adapted to be etachably connected and -having annular grooves adapted to register to provide a mold cavity, each. of said sections furthermore provided with an annular recess open-- ing into the groove of its respective section, and a plurality of recessed rings removably mounted in each of said recesses, the recessed portions of saidl rings opposing said mold cavity, the recesses of one ring being alternately disposed with respect to the recesses of ana'djacent ring.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

PAUL W. LITCHFIELD.

Witnesses C. E. HUMPHREY, GLENARA Fox. 

